Grit collector



Aug; 11, 1942. c. s. WILQEMAN GRIT COLLECTOR Original Filed March 10,.1937 '4 Sheets-Sheet l Aug. 11, 1942. c. s. WILEMAN 2,292,355

GRIT COLLECTOR j 7 Original Filed Mal-ch10, 1937 4 Shee ats-Sheet 2Mull! I Augll, 1942. V j I c. s. WILEMAN 2,292,855

, GRIT COLLECTOR I Original Fild March 10,1955 4 Shets-Sheet 5 Urozz'er77i'Zeman.

11,1942 CLSLWIL EMAIj ,292,855

GRIT COLLECTOR Original Filed jungle, 193'? 4 Sheets-Sheet 4 ammimm a'1' l t i K I fi y gy Patented Aug. 11, 1942 GRIT COLLECTOR Crozier S.Wileman, Lakewood, Ohio, assignorto Link-Belt Company, Chicago, Ill., acorporation of Illinois Original application March 10, 1937, Serial No.2 130,010, now Patent N0. 2,202,475, dated May 28,

Divided and this application February 15, 1940, Serial No. 319,124

. 19 Claims.

ganic material, the organic material being retained in' the stream ofsewage, the washed grit being discharged from the. system.

My invention is adapted to provide means for accomplishing the abovepurpose and doing it in such a way that change in rate of flow andchange in the character of the sewage will have a minimum eflect uponthe operation of the device.

Other objects will appear from time to time throughout the specificationand claims.

The present application is a division of my copending application SerialNo. 130,010 filed in 118 United States Patent Oflice on March 10, 1937,which has now matured into Patent Number 2,202,475, May 28, 1940.

My invention isillustrated more or less diagrammatically in theaccompanying drawings wherein Figure l is a plan view of one embodimentof my invention;

Figure 2 is a section along the line 2--2 01' Figure 1;

I Figure- 3 is a section along the line 3-3 of Figure 2;

Figure 4 is a sectionalong the .line 44 of Figure 2;

Figure 5 is a plan view'of a modified form of the device;

I Figure 6 is a section along the line 6-6 of ure 5;

Figure 7 is a section along the line 'I'I of Figure 6; I

Figure 8 is a view similar to Figure'l, showing a modified form whereina single grit washing of sediment thereon, the sediment sliding bygravity freely down therealong; the other part of the bottom or floorI03 is less sharply inclined. Associated with the sharply inclined floorI03 is .wall I06 into the eilluent trough II2.

I05, and I06 which carry tracks or rails I01 and bounded by end wallsI08. trough supplied with sewage through the channel H0 and dischargingsewage into the tank at a point below the water level through theapertures I I I. I I2 is an effluent trough associated with a weir H3and discharging through an efiluent channel I I4. I I5 is a drip troughcarried on the wall I 06 draining through ports 3H in III, III are floorpanels adjacent the walls I08 also sharply inclined downwardly so as topermit free flow by gravity of the sediment.

I 2I is abridge extendingacross the tank having anti-friction rollersI22, adapted to travel along the tracks I01. I23 is a motorized speedreducer driving a longitudinal shaft I24. On this shaft are drums I25about. which are wound cables I26, I21, the cables being anchoredrespectively attheir ends on the walls I08. I28 is anelectric cableanchored on the wall I08 and wound about a spring reel I29 wherebyelectric current is brought to the bridge. The motor. of the motorizedspeed reducer I23 is automatically reversible so that as the motoroperates it shuttles the bridge back and forth across the tank,reversing at each end of its excursion. The means for accomplishing thisare standard electric control switches which are not illustrated.

Suspended on the bridge I2I is a screw conveyor I30. Its axis is'generally parallel with the floor I03. It is enclosed in a trough I 3|which extends upwardly from the floor I03 across the is a grit plow orb'ack blade interposed between a still less sharply inclined floor I 04adapted to support sediment which may be deposited thereon. The tank isbounded by longitudinal walls the two conveyors and adapted to travelalong the floor of the tank.

Also mounted on the bridge are a pair of flight conveyors comprisingchains I40, flights I, the chains traveling over sprockets I42, I43,I44. The sprockets I44 are driven by a chain I45 from the motorizedspeed reducer I35. These flight conveyors travel along the surface I04and since there is one conveyor on each side of the bridge. theseconveyors scrape across the floor I04 into the hopper formed between thefloors I03, I02 and Ill and in whichever direction the bridge is I09 isan influent moving, the leading flight conveyor scrapes the freshlydeposited sludge down into the hopper where it can be picked up by theplow and the screw conveyors and conveyed upwardly, washed anddischarged.

In the modified form shown in Figures 5, 6 and 7, the rectangular tankhas merely the two inclined floors I02 and lil. Two screw conveyors I30are supported on the bridge l2! and the flight conveyors are omitted. Inthis case, each screw conveyor comes clear to one end of the tank anddoes its work on the sludge in'the tank without the interposition of theflight conveyor, the tank floor being such that all the sludge comesinto the zone of influence of the screw conveyor and scraper.

In the modified form shown in Figure 8 but a single screw conveyor III!is used and it is associated with two grit plow blades or back boardsI52 and I53 supported on the bridge mounted on rocker arms I54 with atrip mechanism adapted to trip the rocker arms at each end of theexcursion of the'bridge so that a grit scraper is always on the rearside of the screw conveyor. The details of this trip mechanism are notshown as it forms no part of the present invention and is a standardengineering product.

I have shown in my specification and drawings a number of modified formsof the device with different shapes of tank, different types of conveyorand washer and various diflerent combinations. Of course, many othercombinations of these same elements or different elements might wardlyabove the level of the liquid across the.

be adopted without departing materially fromthe spirit of my inventionand I wish, therefore, that my showingbe regarded as in a sensediagrammatic.

In general I propose that the agitation will be such as to prevent thesettling out of lighter organic solids, while permitting settling out ofheavier organic solids. This must be regarded, of course, as a generalline'of demarcation. There may be organic solids which will settle,there may be inorganic solids which will not settle. Even some lighterinorganic solids may be carried down with the heavier, and settled, andthe general proposition is that the division line is between certainheavy solids and certain light solids, and the heavy solids are to bedisposed of in one way and the light solids in another.

The rate of rotation of the screw is such as to furnish a churning oragitating effect at the point of emergence so as to wash organics fromthe inorganics allowing these lighter particles to flow or float backinto the tank. Any light organic orfloatable material which may havebeen trapped with the settling grit is agitated by the screw and thrownback into suspension to be carried away by the liquid in the tank.

The organics are prevented from settling, not by the rate of flow of thecurrent in the tank but .by the agitating effect resulting from themovement of the bridge, the scraper, the screw and the grit plow as theytravel through the body'of liquid in the tank. The rate of travel iskept high enough so as to insure constant agitation. at a ratesuflicient to prevent the settling of the light organics while notsufilcient to interfere with the settling out of the heavy inorganics orgrit.

There is always a, flow of liquid through the tank from the influent tothe eilluent when it is in operation. Under some circumstances the rateof flow may be such that the heavy inorganic 2,292,855 materials willremain in suspension. However,

if the tank is-desisned to rely uponthe flow rate for this separation,it will only be accurate and satisfactory with acomparatively small rateof flow variation. Wide variations both above and below the normal rateof flow will result in interfering with the proper operation of thedevice if flow rate alone is relied upon to eflect separation. As flowincreases above the normal the mentation control eiiect of the bodymovable conveying and washing mechanism will be the controlling factor.If the character of the material changes, the rate of speed of bodilymovement and, so the resultant agitation may be changed by thisarrangement, which puts it into the hands of the operator irrespectiveof conditions of flow, to control the point at which separation betweenthe'light solids carried off in'suspension and'the heavy solids settledout takes place. Preferably discharge is over a weir. Preferably the.combined agitator, washer and conveyor extends upweir, preferably theflow through the tank is in the same general direction as the directionof travel of the settled material, though the point of influent andefliuent might be changed and means other than a weir might, if desired,be used.

I claim:

1. A grit chamber for sewage plants and the like comprising arectangular tank having an inclined floor, an influent. passage at oneend of the tank, an eilluent weir at the other, a combined grit washerand conveyor assembly mounted in the tank and means for moving theentire assembly back and forth along the tank to agitate the liquid inthe tank and means for clined floor, an influent passage at one end of,

the tank, an effluent weir at the other, a combined grit washer andconveyor assembly mounted in the tank and means for moving the entireassembly back and forth along the tank to agitate the liquid in the tankand mean for operating the conveyor to collect sludge, convey the sludgefrom the tank, to wash the sludge at the point of emergence anddischarge it at a point removed from the tank, that part of the floor ofthe tank adjacent the weir being -less sharply inclined than theremainder of the tank floor, auxiliary conveyor means mounted formovement with the main conveyor for propelling settled sludge backwardlytoward and discharging it upon the more sharply inclined portion of thetank.

3. A grit chamber forsewageplants and the like comprising a rectangulartank having an inclined floor, an influent passage at one end of thematerials will settle out and the light organic i5 tank, an effluentweir'at the other, a combined tremity or the inclined floor, thecombined washer conveyor assembly for propelling 'sludgebackand conveyorextending across the weir.

7. A grit chamber for sewage plants and the like including a tank havingan inclined floor, influent and eiiluent passages associated therewith,a combined grit washer and conveyor in the tank,

means for bodily reciprocating it along the floor to agitate the liquidcontained within the tank,

wardly toward and discharging it upon the more sharply inclined portionof the tank, means associated with the conveyor assembly comprising alongitudinal sludge plow for collecting sludge and holding it in thezone of influence of the conveyor.

4. A grit chamber for sewage plants and the,

like comprising a' rectangular tank having an incllned floor, aninfluent passage at one end of the tank, an efiluent weir at the other,a combined grit washer and conveyor main assembly, mounted in the tankand means for mov ing the entire assembly back and forth along the tankto agitate the liquid in the tank and driving means for moving theconveyor along the assembly to collect sludge, convey the sludge fromthe tank, to wash the sludge at the point of emergence and discharge itat a point removed from the tank, that part of the floor adjacent theweir beingless sharply inclined than the remainder of the tank floor, anauxiliary conveyor means mounted for movement with the conveyor assemblyand adapted to travel along the less sharply inclined portion of thefloor for propelling sludge backwardly toward and discharging it uponthe more sharply inclined portion of the tank, means associated with theconveyor main assembly comprising a longitudinal sludge plow forcollecting sludge and holding .it in the zone of influence of theconveyor, means for maintaining the sludge plow always on the back sideof the auxiliary conveyor as it moves back and forth in the tank.

5. A grit chamber for sewage plants and the like including a tank havingan inclined floor,

influent and eflluent passages associated therewith, a combined gritwasher and conveyor in the tank, means forbodily reciprocating it alongthe floor to agitat the liquid contained within the tank, means foroperating the conveyor as it is bodily displaced in either direction tocause it to collect material deposited on the floor, propel it upwardlytherealong, agitate it and wash it at the point of emergence from theliquid and means for operating the conveyor as it is bodily displacedin'either direction to cause it to collect material deposited on thefloor, propel it upwardly therealong, agitate it and wash it at thepoint 01- emergence from the liquid, means for dischargingthe heaviersolids from the system and returning the lighter solids to the body 01'the liquid in the tank, the tank having a relatively level floorextending from the upper extremity of the inclined floor, an eflluentweir bounding said level floor onthe side farthest from the inclinedfloor and means connected to the combined washer and conveyor andmovable therewith for propelling settledmaterial along the level floorand discharging it upon the inclined floor.

8. A grit chamber for sewage plants and the like including a tank havingan inclined floor,.

influentandeflluent passages associated therewith, a combined gritwasher and conveyor in pel it upwardly therealong, agitate it and washit at the point of emergence from the liquid, means for discharging theheavier solids from the system and returning the lighter solidsto thebody 01' the liquid in the tank, the combined washer and conveyorincluding a screw convey"- ing mechanism and a scraper. blade movabletherewith along the floor.

9. A grit chamber for sewage plants and the like including a tank havingan inclined floor, influent and eilluent passages associated therewith,-a combined grit washer and conveyor in the tank, means for bodilyreciprocating it along the floor to agitate the liquid contained withinthe tank, means for operating the conveyor as it is bodily displaced ineither direction means for'discharging the heavier solids from thesystem and returning the lighter solids to the body of the liquid in thetank.

6. A grit chamber for sewage plants and the like including a tankhaving. an inclined floor,

influent and effluent passages associated therewith, a combined gritwasher and conveyor assembly in the tank, means for bodily recipro-.

eating the entir assembly along the floor to agitate the liquidcontained within the tank, means for displacing the conveyor withrespect to the assembly as it is bodily displaced in either 'dito causeit to collect material deposited on the floor,.propel it upwardlytherealong, agitate it and wash it at the point of emergence from theliquid, means for discharging the heavier solids" from the system andreturning the lighter solids to the body of the liquid in the tank, thecombined washer and conveyor including a screw conveying mechanism and ascraper blade movable therewith along the floor, the scraper blade beingso positioned that, irrespective of the direction of movement of thecombined washer and conveyor, to hold material collected thereby in suchposition that the screw conveyor will act upon it.

10. A grit chamber for sewage plants and the like including a tankhaving an inclined floor, influent andeflluent passages associatedtherewith, a combined grit washer and conveyor in the tank, means forbodily reciprocating it along the floor to agitate the liquid containedwithin the tank, means for operating the conveyor as itis bodilydisplaced'in either direction to cause it to collect material depositedon the door, propel it upwardly therealong, agitate it and wash it atthe point of emergence from the liquid,

means for discharging the heavier solids from the system and returningthelighter solids to the body of the liquid in the tank, thecombinedsages associated therewith, a combined grit washer and conveyor 'in thetank, means for bodily displacing it along the floor to agitate theinfluent and emuent passages associated therewith, a combined gritwasher and conveyor in the tank, means for bodily reciprocating it alongthe floor to agitate the liquid contained within the tank, means foroperating the conveyor as it is bodily displaced in either direction tocause it to collect material depositedon the floor, propel it upwardlytherealong, agitate it and wash it at the point of emergence from theliquid, 'means for discharging the heavier solids from the system andreturning the lighter solids to the body of the liquid in the tank, thecombined washer and conveyor including a screw conveyor member, and aplurality of scraper blades adapted to be selectively presented one ofthem at a time to the floor of the tank behind the screw conveyor as itis bodily displaced in a forward direction.

12. A grit chamber for sewage plants and .the like including a tankhaving an inclined floor,

'. influent and eilluent passages associated therewith, a combined gritwasher and conveyor in the tank, means for bodily reciprocating it alongthe floor to agitate the liquid contained within the tank, means foroperating the conveyor as tank floor to cause it to discharge settledmaterials upon the inclined floor in the path of the combined washer andconveyor.

13. A grit chamber for sewage plants and the like including a tankhavingan inclined floor, influent and effluent passages associatedtherewith, a combined grit washer and conveyor in the tank, means forbodily reciprocating it along the floor to agitate the liquid containedwithin the-tank, means for operating the conveyor as it is bodilydisplaced in either direction to cause it to collect material depositedon the floor, propel it upwardly therealong, agitate it and wash it atthe point of emergence from the liquid, means for discharging theheavier solids from the system and returning the lighter solids to thebody of the liquid in the tank, a relatively flat floor in continuationof the inclined floor of the tank, a conveyor adapted to be bodilydisplaced along the fiat floor in unison with the combined washer andconveyor, and means for operating the conveyor to cause it to dischargesettled material upon the inclined floor in the path of the combinedwasher and conveyor, the conveyor including flight conveyor membersmovable in a direction atright angles to the direction of bodilydisplacement of the combined grit washer and conveyor.

14. A grit chamber for sewage plants and the like including a generallyrectangular. tank having an inclined floor and influent and eflluentpasliquid contained within'the tank at a rate of bodily displacementofthe combined washer and conveyor as it reciprocates along the floor ofthe tank from end to end thereof will maintain the liquid in acontrolled state of agitation greater than and independent of anyagitation resulting from the flow of liquid to and from the tank.

15. A grit chamber for sewage plants and the like including a tankhaving a liquid inlet, a liquid outlet, and a floor the. angle ofinclination of which is such that settled material will remain at restthereon, tracks associated with the tank walls, a bridge and means formoving it back and forth along them, a conveying mechanism including ascraper blade supported on the bridge and adapted to travel therewithalong the floor, means for controlling the level of the liquid in thetank, a trough projecting above the liquid level in alignment over thescraper blade, the upper end of the conveyor being contained therein, agrit receptacle associated with the trough and movable therewith, thetrough extending beyond the periphery of the tank and adapted todischarge into the grit receptacle and means operating in coordinationwith the reciprocation of the bridge for periodically discharging gritfrom the receptacle.

16. A grit chamber for sewage plants and the like having inlets andoutlets and including a tank having a floor the angle of inclination ofwhich is such that settled material will remain at rest,thereon, tracksassociated with the tank walls, a bridge and means for moving it backand forth along them, a conveying mechanism including a scraper bladesupported on thebridge ,and adapted to travel therewith along the floor,

and forth along them, a conveying mechanism including a scraper bladesupported on the bridge and adapted to travel therewith along the floor,means for controlling the level of the liquid in the tank, a troughextending above the liquid level in alignment with the scraper blade,the upper end of the conveyor being contained therein, a gritreceptacleassociated with the trough and movable therewith, a grithopper positioned along (the line of travel of the grit receptacle andmeans adapted to open the grit receptacle to cause it to discharge intothe hopper when the two are in register.

18. A grit chamber for sewage plants and the like having inlets andoutlets and including a tank having a floor the angle of inclination ofwhich is such that settled material will remain at rest thereon, tracksassociated with the tank walls, a bridge and means for moving it backand forth along them, a conveying mechanism including a scraper bladesupported on the bridge and adapted to travel therewith along the floor,means for controlling the level of the liquid in I v r 2,292,855 thetank, a trough extending above the liquid level in alignment withthescraper blade, the upper end of the conveyor being contained therein,and means for discharging solids from the upper end of the troughoutside of the tank, a relatively flat floor extending beyond the upperedge of the inclined floor, the trough extending above the flat floor.

19. A grit chamber for sewage plants and the like including a tankhaving a liquid inlet, a liquid outlet, and a floor the angle ofinclination of which is such that settled material will remain at restthereon, tracks associated with the tank walls, a bridge and means formoving it back and forth along them, a'conveying mechanism including ascraper blade supported on the bridge. and adapted to travel therewithalong the floor, means for controlling the level of the liquid in thetank, a trough extending above the liquid level in alignment with thescraper blade, the upper end of the conveyor being contained thereandmeans for discharging solids from the upper end of the trough outside ofthe tank, a relatively flat floor extending beyond the upper edge of theinclined floor, the trough extending above the flat floor conveyingmeans movable with the bridge fordischarging settled material from theflat floor to the inclined floor in the path of the scraper blade.

CROZIER s. WILEMAN.

